This invention relates to a copper alloy designed for springs, possessing high strength, desirable spring qualities, and excellent corrosion resistance and electrical conductivity and yet available at low cost, and also to a method of manufacturing the alloy.
Spring materials heretofore used to make springs for electrical machines, measuring instruments, and electrical parts, such as switches and connectors, have been three kinds of alloys, i.e., brass that is inexpensive, nickel silver excellent in spring properties and corrosion resistance, and phosphor bronze with superior spring qualities. However, brass is inferior in strength and other properties needed in springs. On the other hand, despite their excellent strength and spring qualities, nickel silver and phosphor bronze, which contain 18 wt % nickel and 8 wt % tin, respectively, are rather too expensive alloys because of the elements involved and the limitations in working including poor hot workability. Another disadvantage common to those alloys is low electrical conductivity in applications such as component parts of electrical machinery and appliances. A further disadvantage of phosphor bronze, in particular, is inadequate resistance to corrosive attacks. For these reasons there has been a great need for the introduction of an alloy inexpensive but highly conductive and excellent in corrosion resistance and properties useful in springs.